Repenting of Sin Against the Greatest Commandment

“We have not loved thee as we ought, nor cared that we are loved by thee”-Thomas Pollock 

These are a few searching words from a great hymn of repentance. It  sounds strange to our modern conception of sin to think that we need to repent of not loving God as we ought.  But if loving God is the greatest commandment, then failure to love him has to be one of the greatest sins.